Confirmed Exoplanet Discovered 2016

HATS-31 b

A gas giant orbiting the f-type yellow-white HATS-31, located approximately 2,524.4 light-years from Earth.

Key parameters at a glance

  • A radius of 18.38 Earth radii
  • A mass of 279.69 Earth masses
  • Surface gravity around 0.83 g
  • An orbital period of 3.378 days
  • Semi-major axis 0.0478 AU
  • Equilibrium temperature 1,823 K (1550 °C)
  • Distance from Earth 2,524.36 light-years
  • Earth Similarity Index 0.052
  • Travel time at Voyager 1 speed 44,517,133 years

HATS-31 b Planet Profile

Physical Specs

Radius
18.38 R⊕
Radius (Jupiter)
1.640 R♃
Mass
279.69 M⊕
Mass (Jupiter)
0.880 M♃
Density
0.24 g/cm³
Surface Gravity
0.83 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.052
HZ Position Inner
Controversial No

Discovery

Year 2016
Method Transit
Facility HATSouth
Telescope 0.18 m Takahashi Epsilon Astrograph

Size rank in cohort

Rank by radius

#58of 1771

top 3.2%

This planet

18.38R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

Metric Earth HATS-31 b Jupiter
Radius (R⊕)1.0018.3811.21
Mass (M⊕)1.00279.69317.83
Density (g/cm³)5.510.241.33
Surface Gravity (g)1.000.832.53
Insolation (S⊕)1.001,619.410.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 279.690 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 9385460

Gaia DR2

Gaia DR2 3498553232585634816

Gaia DR3

Gaia DR3 3498553232585634816

System

HATS-31

Percentile among Gas Giant cohort

Radius 18.383 R⊕ · percentile 97 / cohort 1771
Mass 279.690 M⊕ · percentile 31 / cohort 1747
Orbital period 3.38 d · percentile 21 / cohort 1533
Distance 773.97 pc · percentile 83 / cohort 1759
ESI 0.052 · percentile 5 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period
3.378 days
Semi-major axis
0.0478 AU
Eccentricity
0.233
Inclination
85.00 °

Year Length

A year here lasts approximately 3.38 Earth days (0.9% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.0478 AU.

Transit Fingerprint

Depth

0.720 %

Duration

4.594 h

Impact parameter b

0.480

Rp / R★

0.090800

Transit midpoint (BJD)

2,456,960.1476

Photometric dip

Transit produces a flux drop of 7,199 ppm lasting ≈ 4.59 h.

Extended Orbital Architecture

Planet / star radius ratio

0.090800

Semi-major axis / stellar radius

5.490

Impact parameter (b)

0.480

RV semi-amplitude (K)

102.000 m/s

Transit mid-time (BJD)

2,456,960.1476

Angular separation (arcsec)

0.06180

Eq. Temperature

1,823K

(1550 °C)

Insolation (S⊕)

1,619.41

Earth = 1.00

Earth Similarity (ESI)

0.052

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched.

Detection Signatures

Transit photometry

A transit dip has been observed from at least one telescope.

Radial velocity

Stellar wobble has been measured spectroscopically.

Discovery Paper

Primary reference

De Val Borro et al. 2016

Instrument

Apogee 4K CCD Sensor

Publication

2016-12

Observation locale

Ground

Host System: HATS-31

Spectral Class

F-type yellow-white

Effective Temperature

6,050 K — hotter than the Sun (5,778 K)

Estimated Age

4.30 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.870 R☉

Stellar Mass

1.275 M☉

Metallicity [Fe/H]

0.00

Extended Stellar Properties

Surface gravity (log g)

4.000 dex

Stellar density

0.275 g/cm³

Systemic radial velocity

-8.70 km/s

Rotational v·sin i

7.01 km/s

Metallicity ratio

[Fe/H]

Distance
773.97 parsec
Light-years 2,524.36 ly
V-band magnitude
13.32 mag
Voyager-speed travel 44,517,133 yr

Multi-band Host Photometry — 14 bands

8.713.713.69B13.32V12.96Gaia12.53TESS13.36Sloan g12.95Sloan r12.78Sloan i11.91J11.62H11.57K11.52W111.52W211.72W38.68W4

Astrometric Data

Parallax

1.264 mas

Total Proper Motion

2.502 mas/yr

PM Right Ascension

-1.16 mas/yr

PM Declination

-2.22 mas/yr

Galactic Cartesian (pc)

x = -0.892 · y = -0.185 · z = -0.414

Equatorial (J2000)

RA 191.70282° · Dec -24.42739°

Galactic ℓ, b

301.588° · 38.432°

Ecliptic λ, β

200.530° · -17.816°

HTM-20 index

202114339

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